X‐linked inheritance is also associated with pathologic mutations including FRMD7 (Xq26.2) and GPR143 (Xp22.3), and FRMD7 mutations are more common than GPR143 in IIN.5 Apart for IIN, FRMD7 mutations are involved in congenital motor nystagmus and GPR143 in ocular albinism, respectively.3 Here, GPR143 is linked to congenital nystagmus.